From bfad56c1ed9b48eb080d93df21af04503afa0567 Mon Sep 17 00:00:00 2001 From: Rene Gassmoeller Date: Mon, 18 Mar 2024 14:18:29 -0400 Subject: [PATCH] Update dynamic topography postprocessor documentation --- .../aspect/postprocess/dynamic_topography.h | 5 ++- source/postprocess/dynamic_topography.cc | 39 +++++++------------ .../visualization/dynamic_topography.cc | 23 ++--------- .../surface_dynamic_topography.cc | 23 ++--------- 4 files changed, 26 insertions(+), 64 deletions(-) diff --git a/include/aspect/postprocess/dynamic_topography.h b/include/aspect/postprocess/dynamic_topography.h index 26c371c8456..83414bb3013 100644 --- a/include/aspect/postprocess/dynamic_topography.h +++ b/include/aspect/postprocess/dynamic_topography.h @@ -47,7 +47,8 @@ namespace aspect execute (TableHandler &statistics) override; /** - * Return the topography vector as calculated by CBF formulation. + * Return the topography vector as calculated by the consistent + * boundary flux (CBF) formulation. * The velocity components store the surface-normal traction, * and the temperature component stores the dynamic topography * computed from that traction. @@ -56,7 +57,7 @@ namespace aspect topography_vector() const; /** - * Return the cellwise topography vector as calculated by CBF formulation, + * Return the cell-wise topography vector as calculated by the CBF formulation, * where indices of the vector correspond to cell indices. * This vector is considerably smaller than the full topography vector returned * by topography_vector(), and is useful for text output and visualization. diff --git a/source/postprocess/dynamic_topography.cc b/source/postprocess/dynamic_topography.cc index f7f3f852cf0..9c8d64d662f 100644 --- a/source/postprocess/dynamic_topography.cc +++ b/source/postprocess/dynamic_topography.cc @@ -519,36 +519,27 @@ namespace aspect ASPECT_REGISTER_POSTPROCESSOR(DynamicTopography, "dynamic topography", "A postprocessor that computes a measure of dynamic topography " - "based on the stress at the surface and bottom. The data is written into text " - "files named `dynamic\\_topography.NNNNN' in the output directory, " - "where NNNNN is the number of the time step." + "based on the stress at the boundary. The data is written into text " + "files named `dynamic\\_topography_\\X.NNNNN' in the output directory, " + "where X is the name of the boundary and NNNNN is the number of the time step." "\n\n" - "The exact approach works as follows: At the centers of all cells " - "that sit along the top surface, we evaluate the stress and " - "evaluate the component of it in the direction in which " - "gravity acts. In other words, we compute " - "$\\sigma_{rr}={\\hat g}^T(2 \\eta \\varepsilon(\\mathbf u)- \\frac 13 (\\textrm{div}\\;\\mathbf u)I)\\hat g - p_d$ " - "where $\\hat g = \\mathbf g/\\|\\mathbf g\\|$ is the direction of " - "the gravity vector $\\mathbf g$ and $p_d=p-p_a$ is the dynamic " - "pressure computed by subtracting the adiabatic pressure $p_a$ " - "from the total pressure $p$ computed as part of the Stokes " - "solve. From this, the dynamic " - "topography is computed using the formula " - "$h=\\frac{\\sigma_{rr}}{(\\mathbf g \\cdot \\mathbf n) \\rho}$ where $\\rho$ " - "is the density at the cell center. For the bottom surface we chose the convection " - "that positive values are up (out) and negative values are in (down), analogous to " + "The exact approach works as follows: At each selected boundary, we compute " + "the traction that acts normal to the boundary faces using the " + "consistent boundary flux method as described in " + "``Gresho, Lee, Sani, Maslanik, Eaton (1987). " + "The consistent Galerkin FEM for computing derived boundary " + "quantities in thermal and or fluids problems. International " + "Journal for Numerical Methods in Fluids, 7(4), 371-394.'' " + "From this traction, the dynamic topography is computed using the formula " + "$h=\\frac{\\sigma_{n}}{g \\rho}$ where $g$ is the norm of the gravity and $\\rho$ " + "is the density. For the bottom surface we chose the convention " + "that positive values are up and negative values are down, analogous to " "the deformation of the upper surface. Note that this implementation takes " "the direction of gravity into account, which means that reversing the flow " "in backward advection calculations will not reverse the instantaneous topography " "because the reverse flow will be divided by the reverse surface gravity. " "\n" "The file format then consists of lines with Euclidean coordinates " - "followed by the corresponding topography value." - "\n\n" - "(As a side note, the postprocessor chooses the cell center " - "instead of the center of the cell face at the surface, where we " - "really are interested in the quantity, since " - "this often gives better accuracy. The results should in essence " - "be the same, though.)") + "followed by the corresponding topography value.") } } diff --git a/source/postprocess/visualization/dynamic_topography.cc b/source/postprocess/visualization/dynamic_topography.cc index f206c4c604b..01817ddd267 100644 --- a/source/postprocess/visualization/dynamic_topography.cc +++ b/source/postprocess/visualization/dynamic_topography.cc @@ -118,25 +118,10 @@ namespace aspect ASPECT_REGISTER_VISUALIZATION_POSTPROCESSOR(DynamicTopography, "dynamic topography", "A visualization output object that generates output " - "for the dynamic topography at the top and bottom of the model space. The approach to determine the " - "dynamic topography requires us to compute the stress tensor and " - "evaluate the component of it in the direction in which " - "gravity acts. In other words, we compute " - "$\\sigma_{rr}={\\hat g}^T(2 \\eta \\varepsilon(\\mathbf u)-\\frac 13 (\\textrm{div}\\;\\mathbf u)I)\\hat g - p_d$ " - "where $\\hat g = \\mathbf g/\\|\\mathbf g\\|$ is the direction of " - "the gravity vector $\\mathbf g$ and $p_d=p-p_a$ is the dynamic " - "pressure computed by subtracting the adiabatic pressure $p_a$ " - "from the total pressure $p$ computed as part of the Stokes " - "solve. From this, the dynamic " - "topography is computed using the formula " - "$h=\\frac{\\sigma_{rr}}{(\\mathbf g \\cdot \\mathbf n) \\rho}$ where $\\rho$ " - "is the density at the cell center. For the bottom surface we chose the convection " - "that positive values are up (out) and negative values are in (down), analogous to " - "the deformation of the upper surface. " - "Note that this implementation takes " - "the direction of gravity into account, which means that reversing the flow " - "in backward advection calculations will not reverse the instantaneous topography " - "because the reverse flow will be divided by the reverse surface gravity." + "for the dynamic topography at the top and bottom of the model space. " + "The actual computation of this topography is handled inside the " + "'dynamic topography' postprocessor, please check its documentation " + "for details about the numerical methods." "\n\n" "Strictly speaking, the dynamic topography is of course a " "quantity that is only of interest at the surface. However, " diff --git a/source/postprocess/visualization/surface_dynamic_topography.cc b/source/postprocess/visualization/surface_dynamic_topography.cc index 1900592faed..8b18c62e0ad 100644 --- a/source/postprocess/visualization/surface_dynamic_topography.cc +++ b/source/postprocess/visualization/surface_dynamic_topography.cc @@ -118,25 +118,10 @@ namespace aspect ASPECT_REGISTER_VISUALIZATION_POSTPROCESSOR(SurfaceDynamicTopography, "surface dynamic topography", "A visualization output object that generates output " - "for the dynamic topography at the top and bottom of the model space. The approach to determine the " - "dynamic topography requires us to compute the stress tensor and " - "evaluate the component of it in the direction in which " - "gravity acts. In other words, we compute " - "$\\sigma_{rr}={\\hat g}^T(2 \\eta \\varepsilon(\\mathbf u)-\\frac 13 (\\textrm{div}\\;\\mathbf u)I)\\hat g - p_d$ " - "where $\\hat g = \\mathbf g/\\|\\mathbf g\\|$ is the direction of " - "the gravity vector $\\mathbf g$ and $p_d=p-p_a$ is the dynamic " - "pressure computed by subtracting the adiabatic pressure $p_a$ " - "from the total pressure $p$ computed as part of the Stokes " - "solve. From this, the dynamic " - "topography is computed using the formula " - "$h=\\frac{\\sigma_{rr}}{(\\mathbf g \\cdot \\mathbf n) \\rho}$ where $\\rho$ " - "is the density at the cell center. For the bottom surface we chose the convection " - "that positive values are up (out) and negative values are in (down), analogous to " - "the deformation of the upper surface. " - "Note that this implementation takes " - "the direction of gravity into account, which means that reversing the flow " - "in backward advection calculations will not reverse the instantaneous topography " - "because the reverse flow will be divided by the reverse surface gravity." + "for the dynamic topography at the top and bottom of the model space. " + "The actual computation of this topography is handled inside the " + "'dynamic topography' postprocessor, please check its documentation " + "for details about the numerical methods." "\n\n" "In contrast to the `dynamic topography' visualization postprocessor, this " "plugin really only evaluates the dynamic topography at faces of cells "